package org.zjframework.traceframe.common.util.aes;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * AES工具类
 *
 * <pre>
 *   因为某些国家的进口管制限制，Java发布的运行环境包中的加解密有一定的限制。比如默认不允许256位密钥的AES加解密，解决方法就是修改策略文件。
 *   替换的文件：%JDK_HOME%\jre\lib\security\local_policy.jar
 * 参考： http://czj4451.iteye.com/blog/1986483
 */
public class AESUtil {
    // 密钥
	public static String key = "AD42F6697B035B7580E4FEF93BE20BAD";
	private static String charset = "utf-8";
	// 偏移量
	private static int offset = 16;
	private static String transformation = "AES/CBC/PKCS5Padding";
	private static String algorithm = "AES";

	/**
	 * 加密
	 *
	 * @param content
	 * @return
	 */
	public static String encrypt(String content) {
		return encrypt(content, key);
	}

	/**
	 * 解密
	 *
	 * @param content
	 * @return
	 */
	public static String decrypt(String content) {
		return decrypt(content, key);
	}

	/**
	 * 加密
	 *
	 * @param content
	 *            需要加密的内容
	 * @param key
	 *            加密密码
	 * @return
	 */
	public static String encrypt(String content, String key) {
		try {
			SecretKeySpec skey = new SecretKeySpec(key.getBytes(), algorithm);
			IvParameterSpec iv = new IvParameterSpec(key.getBytes(), 0, offset);
			Cipher cipher = Cipher.getInstance(transformation);
			byte[] byteContent = content.getBytes(charset);
			cipher.init(Cipher.ENCRYPT_MODE, skey, iv);// 初始化
			byte[] result = cipher.doFinal(byteContent);
			return new Base64().encodeToString(result); // 加密
		} catch (Exception e) {
			//LogUtil.exception(e);
		}
		return null;
	}

	/**
	 * AES（256）解密
	 *
	 * @param content
	 *            待解密内容
	 * @param key
	 *            解密密钥
	 * @return 解密之后
	 * @throws Exception
	 */
	public static String decrypt(String content, String key) {
		try {

			SecretKeySpec skey = new SecretKeySpec(key.getBytes(), algorithm);
			IvParameterSpec iv = new IvParameterSpec(key.getBytes(), 0, offset);
			Cipher cipher = Cipher.getInstance(transformation);
			cipher.init(Cipher.DECRYPT_MODE, skey, iv);// 初始化
			byte[] result = cipher.doFinal(new Base64().decode(content));
			return new String(result); // 解密
		} catch (Exception e) {
			//LogUtil.exception(e);
		}
		return null;
	}

	public static void main(String[] args) throws Exception {
		String s = "hello world";
		// 加密
		System.out.println("加密前：" + s);
		String encryptResultStr = encrypt(s);
		System.out.println("加密后：" + encryptResultStr);
		// 解密
		System.out.println("解密后：" + decrypt(encryptResultStr));
	}
}